Wounds of battle created a need for surgeons. The point of body entry was the choice of battle, not the surgeon. The devices were the knife, saw, clamp, needle and thread. The methods and skills for using the tools were not much different than those of the ship's carpenter or sailmaker. The term “surgery” made no distinction between collateral damage and damage necessary to effect the desired bodily change and that remains essentially true today. Skill with new devices, methods and pharmaceuticals have improved, making elective surgery feasible.
A substantial percentage of elective surgical procedures involve joining or anastomizing tubes that are not joined naturally. This is because there are a large number of tubes carrying essential body fluids for circulation and excretion and they often suffer physiological damage. Such sites in tubes are frequently by-passed with another tube extracted from the body or made of artificial material. A few examples illustrate the variety, e.g., urethras for gastrointestinal disorders, blocked arteries, shunts for dialysis, cerebral spinal shunts and bypasses of scarred fallopian tubes.
In common medical usage the term “anastomosis” is used for joining or grafting two tubular body parts that are conduits for a fluid. The term is derived from the Greek, referring to opening a mouth, originally referring to the mouths of river branches but used by early anatomists for branching tubular body parts including blood vessels and nerves. The terms “side-to-side” and “end-to-side” are used to distinguish between anastomoses that directly join the cut sides of two tubes and those where the transected end of a tube, called a graft is joined to the artificial opening in the side of another tube. The graft is generally described as a body portion with a first end, a second end and a lumen therebetween. The term “lumen” refers to the inside of the tube where some substance flows. Body tubes are also called conduits or vessels. Since conduits can be troughs and vessels can be objects floating through conduits the term “tube” is used here.
Disease in coronary arteries is the leading cause of premature death in industrialized societies. This makes the importance of anastomizing tubes in a coronary bypass so great that surgical methods involving extreme collateral trauma and risk to the patient are justified. In coronary artery bypass graft CABG, surgeons cut, crack and saw their way through the chest to get their hands in place for making anastomoses, which are the necessary to connect coronary arteries distal to the point of narrowing to a blood supply from the aorta. MIDCABG procedures are endoscopic and involve less collateral damage but still represent a severe strain on patients and have replaced CABG procedures in only a small percentage of cases. CABG will remain the gold standard until more compelling alternatives than MIDCABG are found. Anastomoses of coronary arteries are challenging because they are tiny, friable, intolerant of injury and moving with each beat of the heart. The manual skills for sewing extremely small sutures in tiny frail tubes are well perfected by those who perform CABG surgeries but each anastomosis represents a chance for error or stress beyond what the patient can tolerate. To enable these anastomosis to be done at all the heart must be stopped and circulation placed on an artificial bypass machine so the surgeon does not have the added complications of a moving target in a bloody field. This represents further collateral damage. The risk in heart stoppage is always high, but goes up sharply if time on bypass machine lasts longer than an hour. Suturing by hand takes about ten minutes at each site and in a triple bypass operation six sites require an hour. Sometimes the suturing is inadvertently loose, allowing fluid to leak which can cause acute or chronic loss of blood pressure and possible scarring which results in another blockage. In addition to the threat of leakage, fluid mechanics are such that introducing a stream into a tube at a substantially different angle or velocity of flow than is normal for the tube can cause damage. There is a constant search for improved devices and methods for making anastomoses to reduce the possibility of leakage and time on bypass machine.
This search for alternatives has led in two directions, the first to improve the CABG procedure, the second to eliminate it. The first centers on devices inserted in tubes during MIDCABG or CABG procedures to accomplish anastomoses faster and better than suturing thus reducing or eliminating time on the bypass machine, duration of heart stoppage and leakage. There are metal devices and those that look like plumbing fixtures to make anastomoses faster and/or better. The only ones of relevance to the present invention are those that use seals as they can be advanced intraluminally after percutaneous entry. The alternatives for eliminating MIDCABG and CABG procedures involve use of devices and methods originally developed for percutaneous coronary intervention (PCI).
Three inventions involving seals but intended for use in CABG and MIDCABG procedures are summarized here. One device by Akin, Conston, et al in US Patent Application 2001/0044631, consists of two flexible sheets of material of any shape connected around the circumference of an opening near their center, deployed through openings in side-by-side lumens and held by fluid pressure in each tube. It is claimed this seal is more fluid-tight and more quickly installed by the surgeon's hands than is suturing. Their tests conducted on swine tend to bear this out. However, in the event that a seal alone is not so leak-proof as hoped, the claims include an embodiment where adhesive is used for a tighter seal. An associated device, described as a surgical dispenser, is used to hold the compressed flexible sheet as it is manually inserted through the side of body tubes. Akin, Conston, et al in US Patent Application 2003/0088256 A1, describe a similar seal partially held in place by fluid pressure but aided by various configurations of support members deployed inside each lumen and in the opening between them. Again adhesives are included in one embodiment. This device is manually inserted through the side of tubes though an end-to-side version is mentioned with a figure but it is not included in their claims. In a third invention, Spence, et al, in US Patent Application 2004/0097992 A1, claims a device of two flexible vessel attaching segments called “double cuffs,” connected around the opening between them and placed in the lumens of side-by-side tubes where fluid pressure temporarily holds them in place. With this device there is no doubt regarding the temporary nature of this seal because an oval of malleable studded metal segments surrounds the opening in each tube and is attached to the flexible seal. These clamps are pressed through the opening and into the metal oval opposite to accomplish a permanent connection. In these three devices it has not been proven that they are more leak-proof than manually applied sutures but, at the very least they suggest the value of seals. Further it is evident that these devices can be emplaced in less time than the approximately ten minutes it takes to manually suture an anastomosis. Though they appear to have certain advantages over manual suturing, they are limited to CABG and MIDCABG operations.
In the present invention an end-to-side seal is used, temporarily held in place in one tube by fluid pressure, but made permanent by sutures drawing it against the lumen. As a permanent seal it represents one of two methods used to make the anastomosis leak proof. The other is non-manual suturing of the same anastomosis. This combination of seal and suture in the present invention must be better proof against leaks than suture alone or seal alone. Because it requires only seconds to emplace, it provides the advantages of no time on bypass machine and either no heart stoppage or less than a minute. In addition the present invention includes a combination of devices for conducting the necessary operations intraluminally after percutaneous entry thus avoiding all the collateral damage of CABG and MIDCABG procedures.
Long catheters and fluoroscopic devices make it possible to select a point of entry far from the targeted coronary artery. This is called a percutaneous method in the sense that only skin is broken. The site for entry is chosen where there are no interposing body parts between the skin and the tube. Originally the devices and methods introduced at sites in the groin or arm were for the purpose of advancing and inflating a balloon at a narrowing in a coronary artery. Later a stent device was added, now a chemical eluting stent is used to inhibit growth. Each device was an improved invention for intervening at a narrowed, or otherwise damaged, arterial site. The successive devices were invented and patented while the general method continued to be called Percutaneous Coronary Intervention (PCI) and it's practitioners, interventionists. These methods essentially avoid all collateral damage. Catheters were not originally intended to be used for surgical entry to the body. However with appropriate devices and methods they can be. Several inventions, including the present one do so. This represents the ultimate reversal of entry to the surgical field which was originally determined by battle. It also represents a clear distinction between collateral and necessary damage in surgery.
An example of percutaneous and intraluminal entry to the surgical field is found in an invention by Makower in US 2004/0073238, Device, System and Method for Interstitial Transvascular Intervention. It describes an invention for percutaneous entry, intraluminal advancement to a desired location, opening of an artificial port to another blood vessel or organ, tumor or other anatomical structure so that one or more operative devices can be advanced to perform the desired procedure. Several inventions share this object and method, including the present one. Indeed this description represents the longer highway to the surgical field that is the new alternative to the direct road created by battle damage or surgical bulldozing. If each of the highways had been patented by the early anatomist who discovered it, said patents would have lapsed centuries ago. It remains to be seen what devices are devised to travel this road and for what objects. The need for tracking devices is common to catheter-based systems, e.g. fluoroscopic, and those that leave the highways of natural body tracts to venture outside the tracts are likely to need even better tracking devices. Makower describes active and passive orientation detection by means configured of any of a known set of materials that would allow for the radiographic, fluoroscopic magnetic, sonographic or electromagnetic detection of the location of devices in the body. Use of these various known forms of energy for localization is obvious. Two of Makower's objects make it clear how his invention is different from the present one. One object is the use of a coronary vein running parallel to the coronary artery as a bypass conduit while terminating the vein's original purpose as a vein. He terms the tiny space between tubes as interstitial, while transluminal refers to going across the parallel tube lumens. The means of joining is side-to-side. The present invention utilizes the CABG method of a harvested vein graft to bypass the occlusion with its proximal end starting at the aorta and distal end at the coronary artery with both anastomoses end-to-side. Though the overall object of revascularization is the same and both inventions use catheters to advance on similar highways with localization by the usual sources of energy before and after leaving the highway, the intermediate objects, devices and methods for achieving them are quite different. A second object of Makower's device is transmyocardial revascularization which involves evacuating a channel of tissue between vein and left ventricle. This seems as promising as his other method though both may have their own disadvantages. Regardless of potential advantages and disadvantages, these methods for revascularization are quite different from the method of this invention and certain others that involve a graft between aorta and coronary artery. Makower claims applicability to tracts in the mammalian body other than vascular and that the vascular tract is merely a conduit to other fields of surgery. The present invention and others based on percutaneous entry and transluminal advancement of devices make similar claims about generality.
There is a need for devices and methods that achieve revascularization by the method of coronary bypass proven in millions of CABG procedures but with percutaneous entry, intraluminal advancement, cutting tubes for optimal joining of epithelial layers, clamping, delivery of graft, leak-proof anastomosis done without manual manipulation and quickly enough to avoid bypass machine circulation entirely, with little or no heart stoppage and without the trauma and risk of collateral damage. Fulfillment of this need for patients who cannot tolerate more invasive surgical procedures but can tolerate excisional intraluminal surgery would represent a benefit to a far larger population than the 500,000 or so who now tolerate CABG procedures each year.
Two inventions are described below that involve percutaneous entry, transluminal advancement of devices, cutting openings, clamping openings, tracking devices energized by various but obvious alternative forms of electro, magnetic, mechanical energy, snaring guidewires to lead from aorta to artery and use of wire mesh and stents to make anastomoses with the aid of balloons. These inventions and the present invention use the bypass graft common to CABG as a means of illustrating their preferred embodiments but claim greater generality. The present invention does not leave wire or stents in the body but can utilize biocompatible material if there is no desire to use biodegradable material which is absorbed after the anastomosis heals.
Goldsteen, et al in Medical Grafting Methods and Apparatus, US Patent Application 2004/0116946 A1, and LaFontaine, et al in System and Methods for Percutaneous Coronary Artery, US Patent Application 2003/0195457 make claims that are similar, including some that are similar to the present invention. Both the inventions cited describe a method of connecting the aorta and coronary artery target site by a single continuous guidewire. Both use a snare method to accomplish this but Goldsteen describes a device placed in the coronary artery to deflect the guidewire through the wall. Both snare this wire by a loop of guidewire pushed through the wall of the aorta and substitute one continuous wire for the snared pair. Goldsteen utilizes endoscopic fiber optic light to illuminate and view the snare. Both advance a guiding catheter to an exit site in the aorta. Both advance a sharpened guidewire or stylet through the catheter to cut through the aorta wall. Goldsteen enlarges this opening by twisting a threaded conical tip hoping that this may facilitate transfer of macerated, loosened tissues into a larger proximal catheter. Successively larger catheters are twisted and pushed though the opening until the largest, the guiding catheter is pushed through. This guiding catheter has a pair of annular balloons that are inflated on either side of the opening to clamp it. It appears from the figures that the inflation lumens for these balloons are coincident with the catheter wall and if so, that would need correction or explanation. There is no requirement to stop the heart. LaFontaine has one embodiment where the heart is stopped and another where it is not while he utilizes a vacuum device to isolate and stop blood flow before cutting through the aortic wall. No indication is provided about the size of cut but after it is made the everted graft mounted on a coupler is pushed (bare) through the opening where it is reverted to outside out as it travels though the pericardium on the wire between aorta and artery. Several electro, magnetic, mechanical devises in addition to radiopaque markers for tracking and locating the graft end are described. Goldsteen utilizes radiopaque markers and orthogonal fluorescent screens to track and display location of an artificial graft conduit as it moves mounted on the outside of a catheter through the pericardium on the guidewire. The artificial conduit is a stent-like wire mesh with interstices filled with artificial graft material. Then one of several versions of a threaded or barbed tip cuts or grinds its way through the artery wall. The artificial graft is advanced through the opening and its wire ends spring radially inside the artery lumen. In case these do not make good contact a balloon is inflated in the opening to adjust them. This process is repeated at the opening in the aortic wall with rings of barbs on either side of the wall. If it is desired to use a natural graft instead of the artificial one, it is placed inside the artificial graft for delivery and attached after the artificial graft is attached namely to the tube walls by rings of barbs pushed on either side of each wall by balloons. In an alternative embodiment the natural graft is not preceded by the artificial graft. LaFontaine cuts an opening of unspecified dimensions in the artery wall and the reverted graft is pushed inside the artery coaxial with the artery. It might be noted that coaxial alignment leaves the epithelial layers of the graft and tube separate by the full thickness of the graft. Regardless of this, a short cylinder of wire mesh is placed either inside or outside the graft end which is expanded by a balloon to the diameter of the artery. If this is insufficient to keep it in place an alternative embodiment provides a short cylinder of adhesive to hold it. The graft is attached to the aorta in a similar manner. He describes variously shaped wire mesh, stent-like devices and balloons to push them into place to keep the graft attached to artery and aorta.
The present invention utilizes a combination seal and suture grafting device of biodegradable or biocompatible material that is not dependent on wire and glue to hold graft and tube together. It also provides that the intimal layers of graft and tube are in good contact for sure and fast growth—certainly better than is possible with coaxial contact or gross manipulations with balloons and wire mesh. This is accomplished on the graft preoperatively by a cutting template so its ends are cut to the proper angle for intimal contact with the intima of the tubes it joins. This is maintained by cutting instruments that cut openings of the correct size in tubes so as to expose their intimal linings for proper joining of graft and tube. There is no maceration of delicate tubes involved in any cutting and no irritation by repeated driving of metal barbs though their frail walls. Stiff sutures are driven through the walls in a more delicate manner than provided even by manual suturing as no needle precedes the tiny sutures. The suturing of graft is also completed preoperatively so that only the final stitching to the tubes takes place during the operation. This requires only seconds and no heart stoppage. The sole reason for possibly stopping the heart would be to hold the graft against the heart without it bouncing away and this for no more than a minute. The dual balloon clamps of the present invention do not require heart stoppage as a vacuum device might. The present invention's annular balloons clamp on either side of the aortic wall at a distance from the opening so as not to squeeze the end of open tissue in a way that later impairs the union of its intimal layer with the intimal layer of the graft. The graft in the present invention is transported inside a catheter delivery tube where it is protected from inadvertent injury during transport and it does not suffer the double insult of eversion and reversion. The present invention does not involve placing a continuous guidewire from artery to aorta as other means appear less damaging. The present invention provides two techniques for manipulating the obvious electro, magnetic, energy sources for tracking the graft and delivery tube, a delay line between electromagnetic transmitter-receivers and a variation of the century-old Wheatstone's bridge network for detecting tiny differences in electrical signal strength.
The devices, pharmaceuticals and methods for accomplishing PCI are described in numerous publications, e.g., The Interventional Cardiac Catheterization Handbook by Morton J. Kern, second edition, 2004, Mosby, Elsevier Inc. To the extent appropriate, devices, methods, pharmaceuticals and general knowledge from such sources as describe that state of the art are applicable to the present devices and methods in various application situations. Of course things that are appropriate vary with the application. For instance heparin, nitroglycerin and certain other pharmaceuticals, appropriate in a homeostatic application would not be appropriate in an application to fallopian tubes or colon. However catheters would be common to all applications.